Gas burners



P. M. FORNITI May 17, 1960 GAS BURNERS 3 Sheets-Sheet l Filed Aug. 10,1956 P. M. FQRNITI May 17, 1960 GAS BURNERS 3 Sheets-Sheet 2 Filed Aug.l0, 1956 ATTORNEYS May 17, 1960 P. M. Foam-rl 2,936,751

GAS BURNERS Filed Aug. 10, 1956 3 Sheets-Sheet 3 O lh G IIN@ IMI H BY yMy/77,4%

ATTORNEYS United States Patent C) I GAS BURNERS Philip M. Fomiti,Cleveland, Ohio, assignor to Hupp This invention relates to burners andmore particularly to gas burners.

,While the invention is, in certain aspects, of broad utility andapplication, for kpresent purposes it will be disclosed as applied toimproved burners for the generation of infra-red heat of the so-calledtlameless type in which combustion of gaseous fuel and air takes placein the outer surface of the burner element.

For maximum eiciency such burners should operate in'substantially stillair and Vtheefliciency of such heaters is seriously reduced when theburner surfaces are exposed to currents of moving air. For example,particularly in outdoor installations, gusts of wind blowing against thecombustion surface will cause eruptions of llame from the surface,lowering the temperature of the burner surface thereby seriouslyrreducing the rate of emission of radiant energy. Even indoors suchburners are often subject to such currents of air which may 'be producedby ventilators, open doors'or other sources.

In lmany cases radiant burners or heaters of this type are provided witha duct leading away from the burner surface to confine and direct theradiant energy. Such a duct, if it is imperforate and leads directlyfrom the burner surface, will provide substantial protection against`air currents. However, experience has shown that the combustionproducts cannot be satisfactorily evacuated if suchl an imperforateshieldor duct is used particularly in view of the fact that in mostcases -the burners are positioned overhead, with the burner surface`can'also adversely aiect the combustion efficiency of burners of thistype if they are allowed to'enter the region of the burner adjacent theair intake. While various shields have been proposed in the past toprotect the air inlet from' random air currents and Varying windpressures, nevertheless, no satisfactory solution ofwthis problem hasbeen proposed prior to the present in ven` tion.

Y cessive air currents.

2,936,751 Patented May 17, 1960 Y 2 surfaces and the opposite duct wallcomprises an imperforate sheet of material which is transparent to theradiant energy which it is desired to transmit in a given application.The present invention further contemplates the provision of a novelshield assembly surrounding the combustion air intake to protect thelatter against ex- The shield and the secondary duct system cooperate ina novel manner to provide a fully windproof burner assembly.

VIt is accordingly a further object of the present invention to provideimproved radiant heat burners which may be used outdors and underconditions where previous burners of this type have proved to beunsatisfactory,

It is also an object of the present invention to provide" novel shieldassemblies for radiant heat burners which effectively neutralize varyingwind pressures vfrom 'all directions and provide substantially constant`pressure at the air inlet so that the combustionair is entrained at auniform rate for maximum combustion efficiency.

It is a further object of the present invention to provide novel shieldassemblies for radiant heat burners which are of simple, durableconstruction and which Figure 3 lis a transverse section ofthe burnertaken along line 3-3 of Figure 1;

Figure 4 is a 4fragmentary section taken along line 4-f4 of Figure 1;v

FigureS is a `section taken alongline 5.--5 of Figure y l and showingdetails Aof the air intake shield; and

With the foregoing considerations in mind it i'slthe:

principal purpose' and 'object of the present invention toprovideIimproved radiant heat burners which Aare fully protected against windcurrents and which operate with near optimum eiciency even-in highwinds."""

.In accomplishing this and other lobjects the invention contemplates theprovision of a heatdirecting duct assembly leadingaway from thesurfacel'of the burner and a secondary duct system extendingtransversely across the-primary'fheat directing duct assembly whichpermits eiective vevacuation of the combustion productsI @and yet fullyprotects the surfaces of. the burner against wind' currents. In thepreferred from of theinvention, 'one Wallvof the secondary ductcomprises the radiant-burner Figure 6 is Ia side elevation of the shieldassembly shown in Figure 5,

Referring now more particularly to the drawings, the principalcomponents of the burner therein shown are the burner heads 20 and 22,the main heat directing ductl assembly 24 including a duct member 25,the secondary ventilation duct assembly 26 which extends across andforms a part of the duct assembly 24 and the air intake shield assembly28. The burner heads 20 and 22` are secured by a plurality of bolts 30to a frame struc-V 4ture 32 which extends around the periphery of thetwo burnerheads and between the two burner heads. Pref- -erably anattaching bracket 34 is secured to the frameassembly Y32v between theadjacent edges of the two burners. p v l Each of the burner heads 20 andV22 comprises a.

housing 36 which forms a mixing chamber 38 open i ylength of thepassages 42 is such that combustion of the fuel-air mixture occurs onthe outer surfaces of the burner blocks. 'e

At one end the housing members 36 are provided with integral Yfuel-airinlet sections 44 which are pref.

erably open at their top surfaces. An opening is provided in therearwall of each of the sections 44 to accommodate a gas nozzle 45l which isconnected by 'suitable piping to a source of gas under pressure anddirects a jet` ofgas into the chamber'SS entraining air which enters thesection 44 through its open top surface;

In operationa mixture of gas and primary air -is forced through thepassages 42 and burned in or`on vtlielciuter 'l1 surface of the blocks40. Almost immediately'after Athe' operation of the burners is initiatedthe lower surfaces of .the ceramic blocks are heated to incandescenceVand emit radiant energy in the infra-red spectrum which is directed to-the area to be heated bythe duct assembly 24. It is a characteristic ofburners of this type that the substantially flarneless combustionappearing on or in the surface of the ceramic blocks is effectedrwithoutsecondary air supplied to the surface of the ceramic blocks. In fact ithas been discovered in practice that random currents of secondary airsupplied to the lower surface of the ceramic blocks may actuallyinterfere with the combustion process and lower the temperature of thesurface of the blocks thus materially reducing the efficiency of theburner. In recognition of this fact the present invention provides theduct assembly 26 which extends across the duct assembly 24 and which isAeffective to permit satisfactory evacuation of the products ofcombustion from the area at the lower surface of the ceramic blocks 40while preventing the impingement of excess air currents on thecombustion surfaces.

Ihe rear wall and two side walls of the duct assembly 26 are formed by asheet metal U-shaped channel 46 (Figure 3), the rear wall portion 48being notched at 50 and 52 adjacent its opposite ends to permit thesidewall portions 54 and 56 to be bent at right angles to the rear wallportion 48. An evacuation flue assembly 58 comprising a duct ofrectangular section forms the front Wall of the duct assembly 216 and iswelded or otherwise suitably secured to the free ends of the duct endside walls 5.4 and 56. As shown particularly in- Figure l the ueassembly 58 is bent upwardly to promote the flow ofthe hot combustionproducts out of the .duct assembly 26 by convection. Y

Secured to the upper end of the flue assembly 58 by two spaced pairsofrstraps 60 is an arcuate Vshieldr62. The `shield permits substantiallyunrestricted ilow of combustion products out of the ilue assembly whilepreventing or substantially restricting the inward flow of air throughthe flue assembly and the entrance of rain or snow. The open end of theueassembly 58 is further protected against the entry of `air currentsbyshields 64 and 66 which are suitably secured to the top and bottomwalls of the ue assembly 58 and project outwardly therefrom to pointsopposite the lateral edges of the shield 62. As best shown -in Figure 3all of the shield members 62, 64, and 66 extend the full length of theflue assembly 58 to provide maximum protection.

As best shown in Figure 4 a plurality of openings 68 are provided in therear wall 48 of the duct assembly 26 to promote ventilation of the areaaround the burner elements by convection. from air currents by a sheetmetal shieldl assembly 70 which extends the full length of the rear wall48 of .the duct assembly 26 and is secured along its lower edge to theduct member 25 and at'its upper edge is bolted orV yotherwise detachablysecured to a pair of straps 71 and 72 preferably welded to the wall 48.The opposite ends of the shield 70 are spaced a substantial Vdistanceoutwardly of the shield assembly 28. Accordingly, if reverse low occurswithin the duct assembly 26 due to the positioning of theburnerrassembly, or other factors the products of combustion will bevented outwardly of the ends of the shield assembly 28 so as to avoidVcontamination of the incoming primary air flowing into the burner. ItVwill also be noted that under normal conditions all of the combustionproducts will be vented from the outlet of the llue assembly 58 so thatthere is no possibility of contamination of the primary air withcombustion products. A

The duct assembly 26 is completed by an access plate 76y pivotallymounted on the side Wall 56 as at 78 over an access opening 80 to permitmanual ignition of the burner. Where automatic ignition of the unit isprovided for, the igniter assembly is preferably mounted in the opening80.

These openings are protected It is an important feature of the inventionthat the duct assembly 26 is substantially entirely enclosed. Inaccordancewith the present invention the bottom wall of the ductassembly is formed by a sheet of'glass 82 which shields the combustionsurface from air movements within the heat duct member 25. The glasspanel 82 is preferably held in place by a plurality of clips 84 suitablyspaced around the periphery of the panel. f Ordinary lead borax glass,such as window glass, is quite transparent to infra-red radiation in thevisible spectrum where wave lengths are less than `one micron butbecomes increasingly translucent to infrared radiation in the longerwave lengths. In practice it has been found that most applicationsrequire the emission and transmission of infra-red radiation in wavelengths of approximately 3 microns to more than 8 microns. Accordinglyordinary window glass cannot be used in the burner without serious lossof elliciency. ln accordance with the invention a silicon glass soldunder the trade name of Vycor is utilized for the panel 82 since it hasbeen found that this glass permits substantially complete transmissionof radiant energy in the desired wave lengths.

The primary heat duct member 25, secondary venti Vlation duct assembly26 and the burner assemblies are preferably secured together by aplurality of bolt and nut assemblies 86 located at points suitablyspaced around the periphery of the assemblies. Substantial sealing ofthe duct 26 is effected by asbestos gaskets 88 and 90 which are clampedrespectively between the upper' surface of `the Vduct assembly 26 andthe frame structure 32 and between the lower surface of the ductassembly 26 and the flanged upper end of the heat directing duct member2S.

To provide a completely windproof burner assembly the inlet area throughywhich the primary combustion air enters the burner must be fullyprotected against winds approaching the burner from all direction toprovide a constant pressure in the area surrounding the air inlet tothereby assure'entrainment of combustion air by the gas nozzles 45 at asubstantially uniform rate.

Shield assembly 28 which has been provided for this purpose will now bedescribed in detail with particular reference to Figures V5 and 6. Asthere shown shield 28' is preferably disposed substantially directlyover the rear` edge of the air inlet assemblies 44 when the shieldassembly is -installed in the burner. Spaced from and substantiallyparallel to the free edge of the shield 94 are a pair of bales 96 and 98welded to the cover plate 92.

A second pair of baffles 100 and 102 are also welded to the interior ofthe cover plate 92 and extend late-rally of the cover plate from theforward edge thereof to a point, approximately at the` mid-point of thelongitudinal bales 96 and 98. As best shown in Figure 6 the bottom edgesof the respective bailles 96, 98, 100 and 102 are coplanar and arespaced substantially above the lower edge of the cover Aplate 92. Theshield assembly isY completed by' corner plates 104 and 106 which extendaround the front corners of the shieldsubstantially from the ends of thebaffles 10096 and 102-98 and project below Athe lower edge ofthe coverplate 92. Shield-assembly 28 is preferably heldin place byl a pair ofscrews 108 threaded directly into the burner castings. v

The T-shaped assemblies formed by the respective baffles 96 and 100, andbafes 98 and 102, serve in operaair inlet sections 44.

primary air is effected.

The bae 94 seals the space in .the region of; the rear`v` ward lateraledge of the shield assembly 28. It prevents the establishment of avacuum within this area of the shield which actual experiments haveshown is otherwise caused by wind blowing parallel tothe lower edge ofthe cover plate 92. The bafes 104'and 106 serve essentially the samepurpose as the balles 96-102, and are particularly eiective when theambient wind blows diagonally across the corners of the cover plate 92.

Together the bales p-revent turbulence in the region of the primary areaintake and establish and maintain substantially uniform air pressures inthis region to promote uniform and non-turbulent inspiration of primaryair thereby maintaining high burner eiiiciencyV even unde Y adverseambient conditions.

From the foregoing it will be apparent that the abovestated objects andadvantages of the invention have been attained by the provision of'improved burner assemblies which are substantially completely windproofand are thus operable with good eiciency under conditions which precludethe satisfactory operation of prior burners.

The invention may be embodied in other speciicvforms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered lin all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claim rather than by the foregoingdescription,

direction generally normal to the surface of said burner element, anadditional duct assembly extending generally parallel to the surface ofsaid burner element across said .heat directing `duct assembly adjacentsaid burner elecomprising a dishshaped member extending over said airinlet opening, the open side of which-faces said air inlet opening, abaie having one edge secured to one lateral edge of said dish-shapedmember and extending inwardly i therefrom parallel to the bottom wall ofsaid dish-shaped I Y member, la pair of baies extending around therespective and all changes which come within the meaning and v,

corners of said dish-shaped member and projecting from the lower edge ofsaid dish-shaped member, and air directing vanes projecting from saidbottom wall of said dish-shaped mamber .toward said air -inlet opening.

References Cited in the file of this patent UNITED STATES PATENTS792,323 Dudgeon June 13, 1905 1,677,156 Vaughn July 17, 1928 2,051,213Hamilton Aug. 18, 1936 2,379,766 Tweeddale July 3, 1945 2,517,071 WyattAug, 1, o 2,531,139 Lilly et al. Nov. 21, 1950 2,551,823 Buttner et alMay 8, 1951 2,806,465V Hess a Sept. 17, 1957 FOREIGN PATENTS 1,070,317France Feb. 17, 1954 1,134,715 France Dec. 3, 1956 545,339 Great BritainMay 20,y 1942 621,611 Great Britain Apr. 13, 1949

